THE OBOANS OF THE MIDDLE GERM-LAYEE. 



393 



hW 



(B) The Metamorphosis in the Female. Descensus ovariomm. 



The metamorphosis of the primitive embryonic fundaments in the 

 female is in many particulars the opposite of that in the male, inas- 

 much as parts which are made use of in the latter become rudi- 

 mentary in the 

 former, and 

 vice versd (com- 

 pare with one 

 another the 

 diagrams 

 shown in figs. 

 219, 222, and 

 225). Whereas 

 in man the 

 mesonephric 

 ■duct becomes 

 the vas defer- 

 ens, in woman 

 the Mullerian 

 ■duct (fig. 225 

 t, ut, sch) as- 

 sumes the func- 

 tion of conduct- 

 ing away the 

 ■ova, while the 

 mesonephric 

 duct {ug) and 

 the primitive 

 kidney (ep, pa) 

 become rudi- 

 mentary. 



The prone- 

 phric diict in 



advanced human embryos of the female sex is still demonstrable as 

 an inconspicuous structure in the broad ligament and at the side 

 ■of the uterus ; in the adult it has, as a rule, entirely disappeared, 

 except the terminal portion, which is enclosed in the substance of 

 the neck of the uterus, where it is distinguishable, but only by 

 means of cross sections, as an extraordinarily narrow tubule (Beigel, 

 H. Dohen). In many Mammals, as in Ruminants and Swine, the 



rig. 225.— Diagram to illustrate the development of the female sexual 

 organs of a Mammal from the indifferent fundament of the uro- 

 genital system, which is diagrammatically represented in fig. 219. 



The_ persistent parts of the original fundament are indicated by con- 

 tinuous lines, the parts which undergo degeneration by dotted 

 lines. Dotted lines are also employed to sho-w the position which 

 the female sexual organs take after the completion of the descensus. 



71, Kidney ; ei, ovary ; epy epoophoron ; pa, paroophoron ; ky, hydatid ; 

 t, Fallopian tube (oviduct) ; ug, mesonephric duct ; ut, uterus ; sch, 

 vagina ; kl, ureter ; Itbl, urinaiy bladder ; ?ibV, its upper tip, which 

 is continuous with the ligamentum vesico-umbilicale medium ; hr, 

 Tirethra ; vv, vestibulum vaginse ; rm, round ligament (inguinal 

 ligament of the primitive kidney) ; lo', ligamentum ovarii. 



The letters t', ep', ei', U/ indicate the positions of the organs after the 

 descent. 



